# -*- coding:utf-8 -*-
from data_struct.binary_tree import TreeNode, BinaryTree

__author__ = 'gin.chen'
##重建二叉树

"""
输入某二叉树的前序遍历和中序遍历的结果，请重建出该二叉树。
假设输入的前序遍历和中序遍历的结果中都不含重复的数字。
例如输入前序遍历序列{1,2,4,7,3,5,6,8}和中序遍历序列{4,7,2,1,5,3,8,6}，则重建二叉树并返回。
"""


# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None


class Solution:

    # 返回构造的TreeNode根节点
    def reConstructBinaryTree(self, pre, tin):
        # write code here
        if len(pre) == 0 or len(tin) == 0:
            return None
        tree = TreeNode(pre[0])
        tin_index = tin.index(pre[0])
        tree.left = self.reConstructBinaryTree(pre[1:tin_index + 1], tin[:tin_index])
        tree.right = self.reConstructBinaryTree(pre[tin_index + 1:], tin[tin_index + 1:])

        return tree


if __name__ == '__main__':
    pre = [1, 2, 4, 7, 3, 5, 6, 8]
    tin = [4, 7, 2, 1, 5, 3, 8, 6]
    tree = Solution().reConstructBinaryTree(pre, tin)
    BinaryTree().after_order_traverse(tree)
